Process for the manufacture of high molecular weight polymers



Dec. 7; 1948. A. D. GREEN PROCESS FOR THE MANUFACTURE O F HIGH POLYMERS2 Sheets-Sheet l MOLECULAR WEIGHT original Filed sept. 19, 1941 URC@NUAUNQ/ 4 0 A. D.,GREEN R THE MANUFACTURE OF HIGH Dec. 7, 1948.

, PRocEss Fo MoLEc OriginalFilBd Sept. 19, 1941 ULAR WEIGHT POLYMERS 2Sheets-Sheet 2 Patented Dec.` 7, 1948 l PROCESS FQB THE MANUFACTURE 0FHIGH MOLECULAR WEIGHT POLYMERS Arthur' DonaldV Green'. Cranford,

N. J., assignor,

by menne assignments, to Jalco, Incorporated, a corporation of LouisianaQrlginal application September 19, 1941, Serial No. 411,440. Divided andthis application July 6, 1944, Sel'ill N0. 543,680

7 claims. (ci. eac-s3) This invention relates to polymerizationprocesses and apparatus,'relates particularly to continuous lowtemperature polymerization processes; and relates especially to theseparation of the solid polymeryfrom the liquid and gaseous rei actionmixture components without loss of gaseous materials.v

Isobutylene and many other olens polymerize readily either alone. orwith-.other olefins or dioleilns, into very high molecular weightpolymer substances inthe presence of Friedel-Crafts type catalysts atlow temperatures, and the polymeric materials are finding many importantuses.` To the present, however, the material has usually been preparedby a batch process in which areactor vessel istilled with the oleilnicmaterial,

" which 'may beisobutylenealone or may be isobutylene mixed with varyingproportions of a dlolefln such as butadiene, isoprene, pentadiene,dimethyl butadiene or other dioleilns and hovmologues thereof, or mayconsist of other simple oleilns `or mixtures of the other simple olenswith the dioleilns, together with a suitable diluent-reirigerant such asliquid ethylene or a reu frigerant such as solid carbon dioxide, with orwithout an auxiliary diluent .such as ethyl chloride or other lowfreezing substances; The refrigerant preferably cools the mixture to atemperature below 0 C., and usually below 10 C. to -l40 C. or to 165 C.and preferably to a temperature ranging between 78 C. and -120 C. oreven lower to --165 C.

To the cooledvmixture there is then added a suitable Friedel-Crafts typecatalyst such 'as a gaseous boron trliluoride; ora dissolved activemetal halide such as aluminum chloride in solution in a low freezingsolvent such as ethyl or methyl chloride, or carbon disulilde, or propylchloride if ultra low temperatures are not de- 40y sired, or othersuitable solvent which will dissolve from about one-half per cent toseveral per cent of the active metal halide. The polymerization reactionproceeds quickly, and may reach ccmpletion, or the desired percentageoi'iccmpletion4 in a time interval ranging from a fraction of a minuteto about ten minutes, depending in part upon the temperature and in partupon the strength and efiiciency 'of the catalyst used, as

well as the purity of the reacting substances.

` -In the past, when the reaction had reached the desired stage. thereactor was dumped and the n desired solid polymer recovered from thereaction mixture. This procdure, however. is time consuming andexpensive, involving the sudden vaporization of relatively largequantities ol material and it entails some loss of unreacted materialsand'of the remaining dlluent-refrigerant or refrigerant, as well aspotential danger because of the opportunity for escape of explosivevapors into the atmosphere.

The present invention provides a continuous recycling. process by whichthere is a minimum of loss of unpolymerized and auxiliary materials.Broadly, the invention consists of purincation and mixing systems forthe reactants and the catalyst, to which is connected a polymerizationdevice, provided with means for the' introduction of the catalyst andfor removal of the reaction heat. There is also provided a polymerrecovery member including (if desired) a catalyst quenching means, abelt conveyor system for transporting the polymer separated from theexcess diluent-refrigerant and means for washing and purii'ying therecovered polymer, together with a means for removing the solidA polymerfrom the separating chamber with a minimum loss of gaseous materials;anda condensing and purifying system for the volatile substances as wellas separating and other processing means for the polymer.

Thus the invention consists of the process steps, and apparatus members,for mixing the olenic materials and diluent-refrigerant, a reactionchamber, means for preparing the catalyst and discharging it into thereaction chamber, means for rcmoval'oi the reaction heat, may includemeans for quenching the polymerization reaction 5 by the addition of asubstance which is reactive with the catalyst, such as an alcohol,aldehyde or alkali and includes a separating mechanism4 having a closedchamber containing therein a conveyor belt to which the polymerizationmixi t'ure is delivered. upon which a spray of hot water is dischargedto volatilize all of the volatile constltuents in the polymerizationmixture, leaving behind upon the conveyor belt only the solid polymer,together with an outlet for steamy and volatile hydrocarbons, with acondenser for separating the steam from the volatile hydrocarbons aswater. a purification system for the separation of the various volatilehydrocarbons and catalyst if avolatile catalyst is used, andfmeans forremoving the solid polymer from the separating chamber with a minimum ofloss of gaseous hydrocarbons together with means l'or removing themoisture from the polymer.

Thus an object of the invention is to polymerize an olefinic mixture atlow temperature. and to as isopropyl alcohol which serves to conveyremove the polymer from the system continuously without loss ofunpolymerized components of the reaction mixture, while avoiding anydanger or industrial hazard from leakage of explosive gases. Otherobjects and details of the invention will be apparent from the followingdescription when read in connection with the accompanying drawingswherein:

Figure 1 is a diagrammatic view of the apparatus of the inventionillustrating the process steps of the invention; and

' heat of reaction from the coll I8 to the solid cai- Figure 2 is aperspective view of the polymer.r

separating member of the invention.

This application is a division of my copending application Serial No.411,440 filed September 19, 1941, now U. B. Patent 2,384,298, datedSeptember 4, 1945.

Referring to the figures, there is provided a chamber member I equippedwith a plurality of feed'lines, 2, 8 and l, of which feed lines 2 and 8may be used for the delivery to the mixing chamber. of the variousreacting materials such as isobutylene, butadiene, thediluent-refrigerant such as liquid ethylene, if it is used, or a simplediluent such as ethyl or methyl chloride if such is used.

The feed line 4 preferably is used for the delivery of recycled materialsuch as recovered and recycled oleflnic materials 'or recoveredandrecycled diluent-refrigerant, or recovered and recycled diluent. f'

Adjacent to the mixing chamber I is a second mixing system 5 which isused for the preparation of the catalyst. If boron trifiuoride is usedfor catalyst, this may consist merely of a pressure tank containingliquefied boron trifiuoride. If aluminum chloride or analogous solidcatalyst is used, the member b may represent a dissolving and purifyingsystem to which recycled catalyst solvent is delivered through a feedline B, and fresh catalyst material 'is delivered through feed line 1.The mixing chambers'l and 5 are connected, respectively, throughtransfer lines 8 and 9, to feed measuring pumps II and I2 and furthertransfer lines I4 and I6 to the polymerization reactor i6 which ispositioned within the cooling chamber I1. The transfer lines may conductthe streams through coolers (not shown). The .polymerization reactor I6preferably consists of a spaced internal coil of tubing.

Within the chamber I1, surrounding the coil i8, there is positioned thedesired refrigerant.y

If the refrigerant used is lliquid ethylene, the chamber is preferablyclosed and provided with supply and discharge lines as shown. Of these,the feed line I8 may be used forthe supply to the chamber I1 of thediluent-refrigerant which may bon dioxide. In this instance the line I8serves for discharge of the volatilized carbon dioxide, and the line 2|serves as a drain for the low freezing liquid. The catalyst transferline Il is connected to the coil I8 at several points, one connectionbeing preferably comparatively near to the entrance end of the tube,conveniently about onequarter of the length of the tube. sufficientlength of tube being allowed to permit of the cooling of the mixed olensto substantially the temperature of the refrigerant in the coolingchamber Il.

The polymerization tube I6 is brought out .from the chamber I1 andconnected to a quench mixer 22 to which a catalyst quenching materialsuch as ethyl or isopropyl alcohol is supplied by a transfer line 28 andla. pump 24 which draws a supply from a feed line 28. The quenchedreaction mixture is then delivered through a transfer line 28 into aseparatory chamber 21 on to a conveyor belt 28.

The above disclosure shows a coil polymerization system with externalcooling, the polymerization occurring within the coil. It is notnecessary for this invention that such coil type of cooling system beused. Instead, a pot type of relactor may be used with means for thedelivery of the reactant and catalyst thereto, means for the cooling oithe reactor, reactant supply means, and means for the outflow of thepolymerization mixture with the contained solid polymer. In thisembodiment "internal coollng'may be utilized with a sufcient quantity ofa refrigerant such as liquid ethylene or liquid methane or solid carbondioxide to provide the desired low polymerization temperature. Theoutflow or discharge pipe from any of these alternative reactors may beconnected to the pipe I6, as shown in Fig. l, to deliver thecatalyst-containing suspension or slurry to the quenching device 22 andduci'I 2B, and from the duct 26 to theA conveyor belt 28.

The conveyor belt 28 may consist of a thin steel or bronze sheet, or mayconsist of a wire mesh or a fabric mesh, or a "proofed fabric meshcovered with a substance such as synthetic polymer or other materialwhich does not lose too much of its elasticity at relatively lowtemperature and is be liquid ethylene, may be liquid propane, or

may be other suitable low. boiling substances including sulfur dioxide.ammonia and other appropriaterefrigerants. When usingexternal cooling,there is normally used a diluent but not a denser 8,2 by which vaporsfrom the hot water are diluent-refrigerant -iwhich acts by vaporizing).

` A suitable discharge lline I8 is provided for the j'removal ofvaporized refrigerant. This line is preferably connected to a compressorand cooling system '(not shown) for the-recycling of the refrigerant. vA drain pipe 2I is also provided for the removal of `,thediluent-refrigerant in case of need. -In theevent that solid carbondioxide is used not injured by steam or by the materials beingvaporized. Adjacent to the top surface of the belt 28 there is provideda steam and hot water spray 29 supplied through a feed line 8|. Adischarge line 82 is also provided for the removal of volatilizedhydrocarbon substances including any diluent-refrigerant which mayv havelbeen added in the mixing chamber I, and any simple diiuentf which mayhave been added; as well as the cat.

alyst solvent. The line 32 is connected to a con'- condensed andseparated in the receiver 3l. The volatile hydrocarbon materials aredelivered through a transfer line 88 to a purification system 21 fromwhich they are returned through lines 4 and 8,' respectively. to theolefin mixing system and catalyst preparing system.

The solid polymer delivered fromthe transferA I line 28 is processedwith hot water and steam on the belt 28 and any traces of solublematerial l such as the quenching alcohol, if isopropyl alcohol is used,and a substantial portion of the quenched catalyst, fall from the belton the bottom of the separating chamber 21 from which they are withdrawnby a discharge line 38. If iso- Y propyl alcohol is used, it may berecovered by the 76 appropriate distillation processes from this wastewater. The belt 2l passes through a partition Il in the separatorychamber 21 through a device shown in greaterdetail in Figure 2. Beyondthe partition -39 there is provided a sealed chamber and an end memberIi to the separating chamber 21. member Il within the sealed chamber,there is provided a pressure of steam or inert gas in excess of thepressure within the chamber 21, which is supplied through a feed line42. This pressure prevents the passage of combustible or toxic vaporsthrough the partition 38, and results in the delivery o! all' of thevolatile materials through the line 32 to .the purification system.

From the sealed chamber the polymer is carried out -through thepartition 4i on the belt 28 to an exterior roll I3, upon which the solidpolymer is disengaged from the conveyor fbelt 2l.

The polymer may then, i! desired, be dried by suitable means as shown.

In practicing the invention, the container l is filled with the desiredlsooleflnic material or mixture such as isobutylen'e, -together with asuitable diluent-refrigerant, preferably liquid ethylene, the respectivematerials being delivered through the pipe lines `2, 3 and I.Slmu1taneously,the catalyst container I is illled with the desiredsolution of aluminum chloride or other active halide catalyst.preferably in solution in an alkyl halide such as ethyl or methylchloride or in carbon disuliide or other suitable solvent to form acatalyst solution. The oleilnic mixture is delivered by the pump II tothe reaction chamber or polymerization tube i8 within the coolingchamber I1. the tube being immersed in a suitable refrigerant,preferably liquid ethylene, within the cooling chamber i1. l

Simultaneously, the catalyst solution is delivered through the pipelines 9 and I! by the pump i2 to the polymerization coil I8 atconvenient points along its length as indicated. l

The polymerization occurs in the coil to yield a slurry of solid polymerin the stream oi' diluente refrigerant. This slurry is discharged fromthe lower end of the polymerization tube II into a quenching chamber 22,.to which a supply of a quenching medium such as methyl. ethyl, propyl'tained s. steam pressure higher than the mainvmum vapor pressuredeveloped in the chamber 21 Between the partition Il and the end orhigher alcohol or other oxygenated or alkaline substance is supplied.The alcohol or other quenching substance reacts with the aluminumchloride in the solution :to destroy its catalytic power. r

This quenching apparently is accomplished by a metathetical reactionwhich converts the aluminum chloride into an oxygenated or othercompound,l Iperhaps a double compound with the alcohol, which is of suchlow catalytic power, or

so wholly lacking in catalytic' power, as to pre1- o vent the furthercatalysis of residual polymeric substances during the warming-upoperation.l

The slurry is lthen discharged through the pipe line 2E on to the belt28, where it is washed and brought up nearly to the temperature oiboiling water by a spray of hot water and steam delivered from the pipes29 and 3|. The -tem-perature of boiling water or near to thistemperature is sufnciently high to volatilize all of thediluent-refrigerant, all of the residual oleilnic mixture and all of thecatalyst solvent, as well as some of the alcohol if the lower alcoholsare used. The residual catalyst and water fall to the bottom oi thechamber 21 and are drained away through the drain pipe 38. The polymerlis carried between rolls in the partition while on the belt 28 into thes-ealed 'chamber 40 within which there is main- 75 `feed stream or tothe The maintenance of relatively high steam pressure in the sealedchamber, Iii causes a steady countercurrent of steam to pass between therolls in the partition 39 over the polymer. carrying with it the lasttraces of hydrocarbon substances and carrying all of them upward:through the vapor outlet pipe line 32 to the'cpnclenser 33 andseparatory receiver 35 from which the aqueous liquid portion is drainedby way of the pipe line shown and the gaseous or organic liquid portionsare led through the pipe line 3S to the puriilcation system 31 forrecycling, if desired. Simultaneously; the

The system above described is particularly advantageous forpolymerization reactions in which aV partial polymerization only occurs,leaving a substantial quantity of reactants, diluent-refrigerant andcatalyst solvent to be removed from the solid polymer, since the systemis particularly convenient for the necessary recycling operations.

Alterna-tively, especially when the polymerization reactionis producingsimple polyisobutylene. relatively `small unpolymerizedespecially ifsolid carbon dioxide is used as the refrigerant, and under thesecircumstances, recycling is not necessary. 'I'he above system is,however, particularly advantageous because of the reductiom-,otindustrial and re harzard by avoidingthe discharge of any combustible orpoisonous carbonaceous materials into the atmosphere of the workroom. f

The above disclosure presents a tube reactor, in which most ot thecooling is obtained by a cooling Jacket around the reaction chamber. Thesysteme! the invention is equally applicable to an overilow reactor inwhich a mixture or diluentrefrigerant and olefin material iscontinuously delivered to a reaction chamber such as a reaction kettle,with or without a cooling jacket for refrigerant; and a catalyst isadded either to the rapidly` stirred kettle contents, and a continuousoutput stream of polymer slurry withdrawn to the quenching device andsealed chamber, as shown in the above disclosure. Batch typereactorkettles are readily modified for continuous service by providing anoverflow' outlet from which the overflow stream is taken to thequenching means and separatory chamber. As the reactor means. it issatisfactory to use a simple :lacketed kettle conveyor upon which thepolymerization reaction occurs-may be utilized, or a cardoid type ofreaction kettle with power stirring mechanism may also be used. f

It should be noted that the device of the invention as above disclosed`is particularly advantageous for the making of either solid, semiesolidor liquid polymers. Ii' solid polymers are made, they are present 4as aslurry in a relatively non-viscous liquid and are readily handled in thedevice of the invention. lIn making liquid polymers, they mix with ordissolve in the diluent-refrigerant, ii such is used, or remain liquidin the coil if a diluent or diluent-refrigerant is not used, andaccordingly are equally readily handled.

Thus the practice of the invention provides a recycle system in whichthe olefinic materials are mixed, chilled to low temperature, mixed in aamounts only of material. remain with a stirrer; or a belt enea-eri 7 Ypolymerization 'coil with catalyst solution. passed rapidly through thepolymerization coil at low temperature to a separating chamber, whereunpolymerized olens, diluent-rei'ri'gerants, quenching material -andcatalyst solvent are separated from the polymer, without loss oivolatile organic material, and the solid polymer dried while the gaseousoleiinic material. catalyst solvent and quenching material are separatedand puriiled for.

the preparation of further portions oi polymerization mixture andcatalyst solvent.

closed to the atmosphere, the improvement comprising delivering saidpolymerization mixture from said reaction zone to a treating zone closedto the atmosphere, segregating the solid polymer from the liquidcomponents of the polymerization mixture while conveying the polymeracross the treating zone, spraying and washing the solid polymer withwater as itis so conveyed removing a stream of the resulting volatilizedcomponents and-.a stream of water from the treating zone, then squeezingsaid polymer from said treating zoneintc an enclosed sealing zonewherein an inert gas ismaintained at a pressure which exceeds thepressure in the treating zone, thereby preventing the escape of volatilecomponents from the treating zone into the sealing zone, kand furtherconvey-ing the solid polymerl through the sealing. zoneand finally:squeezing it out of said sealing zone. t

2. In a process for the recovery of'solid isooleilnic polymer productfrom slurries thereof in liquid feed components ofA polymerized coldreaction mixture comprising isobutylene and prepared in an enclosedreaction zone at a temperature between 0 C. and4 .-165 C. in thepresence of a Friedel-Crafts catalyst, the improvement comprisingdelivering said reaction mixture into an enclosed separating zone,straining said mixture to separate the liquid components from the solidproduct, supporting and conveying the solid product across said zonewhile separating a portion of the liquidby straining, washing the solidproduct with hot water to volatllize a portion of the vaporizable liquidcomponents that remain unseparated `from the solid product by straining,

withdrawing a stream of volatilized vapors and draining strained liquidsfrom the said separating zoneforcing the separated and washed solidproduct from the separating zone into: an enclosed sealing zone whereinsteam is maintained l at a suiilciently high pressure to force saidsteam .said inert gas comprises steam.

to pass into said separating zone countercurrent to the direction o!travel of the solid polymer product. thereby preventing the passage ofvolatilized components oi the reaction mixture from the separating zoneinto the sealing zone along with the solid product, and forcing thesolid product out of the sealing zone.

3. The process as described in claim 2 wherein said solid polymerproduct is finally heat-dried.

4. The process as described in claim i wherein 5. The process asdescribed in claim 1 wherein saidinert gas comprises nitrogen.

6. The process'as describedY in claim l. wherein the ,inert gascomprises carbon dioxide.

7. In the process of producing dry, solid high molecular weight.olefinic polymers prepared by cooling a polymerizable liquid feedcontaining isobutylene to a temperature within the range of and solidpolymer product, mixing said stream in an enclosed treating zone withhot water; thereby quenching and removing catalyst from the polymerproduct and also vaporizing unpolymerized feed from the withdrawn streamof' reaction mixture, `separating the solid polymer product from the hotweten, withdrawing a stream of said vaporized feed and a streamcontaining said hot water from the treating zone, squeeze-passing aREFERENCES CITED The 'following references are of record in the tile qithis patent:

,l UNITED 'STATES PATENTS Number Name Date 2,051,840 Gerhart Aug. 25,1936 2,138,895 Wiezevichu Dec. 6, 1938 2,142,910 Moncriei et al y Jan.3, 1939 FOREIGN PATENTS Number Country Date 493,453 Great Britain Apr.20, 1938 491,739 Great'Britain Sept. 8, 1938 379,029 Italy ..7 Mar. 5,1940

